The invention pertains to pump control systems. More particularly, the invention pertains to such control systems, which include processors programmed to reconfigure the inputs in response to faults detected therein.
There are numerous applications where it is desirable to use two or more pumps on a cyclical basis for maintaining the level of fluid in a sump or a tank. The use of multiple pumps increases overall system reliability and extends the time period during which any one pump may be kept in service.
Prior products are known for the purpose of cyclically energizing the members of a group of pumps. One known product incorporates hardwired pump alternator circuitry in combination with two pumps for maintaining the level of fluid in a sump or a tank. A float or a pressure switch is often associated with each pump. The float or pressure switch of each pump provides feedback so as to determine when to energize a selected pump. At times, the feedback is also used to determine when to terminate energizing of that pump.
Some of the known pump alternator systems use current sensors in the feedback path to determine when a pump should be energized. Such sensors tend to be more expensive than desired in many types of products. In addition, known systems physically associate a float switch or a pressure switch with a particular pump. There is usually no circuitry to permit reallocation of float switches or pressure switches among available pumps.
There thus continues to be a need for cost effective, reliable pump alternator systems. Preferably, such systems would incorporate relatively inexpensive feedback elements and could be expandable to more than two pumps. Also, it would be preferred if feedback sensors could be dynamically reallocated in response to a sensed failure.
A software driven pump control system includes a processor programmed with control instructions that respond to a plurality of fluid level inputs. Processor outputs control the operation of a plurality of pumps.
In one aspect, a pump control system can be implemented with a plurality of pumps whose functions such as lead pump, lag pump can be reassigned by the control program to extend pump life. Level indicating signals from a plurality of float or pressure switches provide a basis for energizing and de-energizing the pumps.
In a pump alternator system, two pumps can be controlled with, for example, four fluid related feedback inputs. The pumps can be alternately energized. Alternately, lead and lag functions can be assigned and reassigned based on running time, elapsed time or the like.
The feedback signals can be generated by float switches, pressure switches or the like without limitation. Pump drive characteristics can, if necessary, be taken into account in the control instructions.
Feedback switch fault conditions can be detected and functions such as lead, lag, control and high level can be reassigned dynamically in real time. In such instances, the system will function substantially normally in the absence of one or more normally expected inputs. Two different feedback signals can fail and the associated functions reassigned.
In yet another aspect, a standardized pump control module includes a processor with associated control instructions. The instructions can be stored in rewriteable read only memory, EEPROM.
Input connectors, coupled via input interface circuitry to the processor, can be coupled to a plurality of fluid related sources such as float or pressure switches. Output connectors, coupled via output interface circuitry to the processor, can be coupled to a plurality of pumps.